The invention pertains to the field of electrically operated remote-controlled lamps capable of being adjusted in a three-dimensional pattern.
A number of applications exist where it is desirable to mount an adjustable lamp, such as a floodlight or spotlight, upon a vehicle, boat or other installation whereby the lamp may be remotely operated such that the light beam will sweep both horizontally and vertically. A number of manual devices are available to produce this type of adjustment, and such devices usually employ control handles and shafts, Boden wires, and other cable-type connections where remote operation of the lamp is desired.
Spotlights for automobiles, for instance, have long been available wherein the control mechanism for the spotlight passes through a windshield pillar or wall of the vehicle passenger compartment and protrudes into the compartment wherein the control handle is accessible to the occupant. This type of remote-controlled lamp is no longer permissable under automobile safety regulations due to the protrusion of the handle into the passenger compartment. Also, it is often desired to place an adjustable lamp at a location on a service vehicle remote from the cab, or at the bow or stern of a boat, and with this type of installation an electrically controlled lamp is usually required in that other types of lamp control are difficult to install when the control apparatus is spaced more than a few feet from the lamp itself.
Those electrically operated lamps presently available are of a relatively large size and are expensive to manufacture and assemble, resulting in this type of lamp being used only in those installations wherein cost is not of prime significance. Many electrically powered remotely operated lamps use a yoke-type support for the lamp housing, and the most common construction is to place the mechanism for producing horizontal rotation in the base of the lamp pedestal, while the mechanism for producing the vertical adjustment is mounted in the lamp housing. This type of construction results in a bulky lamp base, and a complicated and costly assembly. Additionally, conductor rings and brushes are often used to transmit electricity to the lamp housing, and this type of electrical transmission is not dependable due to the electrical contacts becoming soiled and nonconducting.
Another disadvantage with available electrically controlled lamps lies in their susceptibility to damage due to the lamp being inadvertently struck or turned manually, which often results in rendering the lamp drive mechanism inoperative. For instance, electric-powered lamps mounted upon vehicle roofs and the like are subject to being brushed by branches and such externally applied forces to the lamp housing can strip gears, shear pins or otherwise damage the drive mechanism.
Electrically driven lamps of previous construction are also susceptible to damage from vibration, particularly when mounted upon boats and motor vehicles, and vibration forces imposed upon the lamp while being operated can become objectionable particularly when using a spotlight filament.
Prior art illustrating electric motor devices for adjusting lamps is shown in U.S. Pat. Nos. 1,611,267; 2,859,331 and 3,075,073. Disadvantages of the above type to which the devices shown in these patents are subject, are overcome by the construction of the invention.